Development of an Ultra-finishing technique for single-crystal diamond substrate utilizing an iron tool in H2O2 solution

In this study, an ultraprecision finishing technique was developed and demonstrated to achieve an improved diamond surface. This finishing technique utilizes hydroxyl radicals (OH radicals) generated on an Fe catalyst tool in H2O2 solution. To demonstrate the feasibility of preparing an ultra-smooth diamond surface over a specific area, an Fe catalyst tool was scanned over a contact area on a diamond substrate in H2O2 solution, while the scanning speed, rotating speed, and contact load were controlled. The area on the diamond surface that had come in contact with the Fe catalyst tool was observed using scanning white light interference microscopy and atomic force microscopy. Moreover, the wear track of the Fe catalyst tool was observed from the viewpoints of chemical composition and surface morphology. The obtained results show that low concentrations of H2O2 solution play an important role in improving the surface roughness and to enhance the material removal rate. Moreover, it turned out that an atomically smooth diamond surface on a specific area can be fabricated by our proposed method. These results provide useful information for the preparation of atomically flat surfaces and microscopic structures on diamond substrates. (C) 2016 Elsevier B.V. All rights reserved.